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Biomedical subjects

M Buemi

Publications and source records attributed to M Buemi.

At least 127 records · Page 7Linked to original sources
PubMed1978

[Regulation of the renin-angiotensin-aldosterone system. Role of the prostaglandins].

PRA (in the supine and erect subject) and urinary sodium before and after acute treatment (100 mg i.m.) and chronic treatment (100 mg per os for 8 days) were examined in two groups of subjects with no signs of cardiovascular or renal disease. It was found that indomethacin, which is a well-known inhibitor of prostaglandin synthesis, reduced PRA levels in basal conditions and as a result of postural stimulation, without causing any appreciable change in urinary sodium. Regulation of the PRA on the part of the renal prostaglandins is postulated and its probable mechanisms discussed.

Adrenal Cortex↗
PubMed1978

Effect of prostaglandin A on renin secretion in the dog.

The role of PGA on the release of renin in the anesthetized dog has been studied. The infusion of prostaglandin for 60 minutes at a dose unable to cause pressor modifications (2 microgram/kg/min) was shown to increase the plasma renin activity (PRA); this effect was inhibited by propranolol and strengthened by aminophylline.

Aminophylline↗
PubMedDate not supplied

Serum ionized magnesium levels in type 2 diabetic patients with microalbuminuria or clinical proteinuria.

BACKGROUND/AIMS: The association between microalbuminuria and magnesium depletion is a controversial issue, and serum ionized magnesium levels have not been previously studied in patients with different grades of diabetic nephropathy. Therefore, the aim of this study was to evaluate circulating ionized magnesium concentrations in patients with non-insulin-dependent diabetes mellitus (NIDDM) and incipient or overt diabetic nephropathy. METHODS: We measured fasting plasma glucose, creatinine, creatinine clearance estimate, total cholesterol and triglycerides, and serum ionized magnesium (ion-selective electrodes, ISE) in 30 NIDDM patients with urinary albumin excretion rate (UAER) <20 microg/min (normoalbuminuria), 30 NIDDM patients with microalbuminuria (20 < UAER < 200 microg/min), 30 NIDDM patients with clinical proteinuria (UAER >200 microg/min), and 20 healthy subjects. RESULTS: Serum ionized magnesium levels were significantly reduced in diabetic patients when compared to control subjects (0.39 +/- 0.06 vs. 0.58 +/- 0.05 mmol/l, p < 0.001). Moreover, diabetic patients with microalbuminuria or clinical proteinuria showed a significant decrease in serum ionized magnesium with respect to normoalbuminuria group (normoalbuminuria: 0.45 +/- 0. 02 mmol/l; microalbuminuria: 0.36 +/- 0.05 mmol/l, p < 0.001; clinical proteinuria: 0.35 +/- 0.04 mmol/l, p < 0.001). Serum ionized magnesium showed a significant negative correlation with plasma HbA1c and triglycerides in both microalbuminuria and clinical proteinuria groups. Multiple linear regression analysis showed that circulating ionized magnesium levels decrease together with the increase of plasma HbA1c and triglycerides in NIDDM patients with incipient or overt nephropathy, also after adjusting for age, sex, BMI, diabetes duration, systolic and diastolic blood pressure, hypoglycemic therapy, plasma creatinine, creatinine clearance, plasma cholesterol and fasting glucose. CONCLUSIONS: Microalbuminuria and clinical proteinuria, as well as poor glycometabolic control and hypertriglyceridemia, are associated to relevant alterations in magnesium metabolism, and the measurement of serum ionized magnesium seems to represent a useful biochemical tool for the study of magnesium disturbances in patients with different grades of diabetic nephropathy.

Albuminuria↗
PubMedDate not supplied

Plasma leptin concentrations in relation to sick euthyroid syndrome in elderly patients with nonthyroidal illnesses.

BACKGROUND: Leptin, the ob gene product, seems to be involved in regulating energy expenditure in humans, but its role in the pathophysiology of the energy imbalance in chronically ill patients is largely unknown. OBJECTIVE: To evaluate plasma leptin concentrations and thyroid function in elderly patients with nonthyroidal illnesses (NTI). METHODS: Sixty-four NTI elderly patients (75.0 +/- 6.3 years, 27 males and 37 females) and 21 age- and sex-matched healthy controls (73.0 +/- 5.5 years, 9 males and 12 females) were enrolled in the study. In all subjects tri-iodothyronine (T(3)), thyroxine (T(4)), reverse T(3) (rT(3)), free T(3) (fT(3)), free T(4) (fT(4)), TSH, and plasma leptin concentrations were measured. Nutritional status was also evaluated in all subjects studied by the measurement of body mass index (BMI), lymphocytes, serum iron, hemoglobin, plasma albumin, transferrin and total cholesterol. RESULTS: The data on thyroid hormones enabled us to identify three groups: group A, subjects (15 patients) with T(3) and fT(3) levels comparable to those of controls; group B, subjects (25 patients) with T(3) and fT(3) levels lower than controls and rT(3) levels comparable to those of controls; group C, subjects (24 patients) with T(3) and fT(3) levels lower than those of controls and high rT(3) levels. The patients of group C showed lower plasma leptin levels than the controls, 6.6 (5.5-14.2) and 16.3 (7.2-23.7) ng/ml (median with interquartile range in parentheses, p < 0.05), respectively. Females also showed higher plasma leptin levels than males in the controls, group A and group B, but not in group C. Moreover, plasma leptin concentrations were directly correlated to BMI in all the groups studied, while a negative correlation between leptin and rT(3) was detectable in group C (r = -0.44, p < 0.05), also after adjusting for BMI and sex. CONCLUSIONS: The concurrence of modifications in plasma leptin and thyroid hormones concentrations found in elderly NTI patients with a sick euthyroid syndrome could reflect a particular neuroendocrine status, leading to a reduction in the catabolic processes in the course of chronic diseases.

Aged↗
PubMedDate not supplied

Recombinant human erythropoietin inhibits the cutaneous vasodilatation induced by acetylcholine.

We investigated by means of telethermography the contractile response of cutaneous vessels to recombinant erythropoietin (rHuEPO) and the effects of this hormone on the vasodilatation induced by either acetylcholine, which is endothelium-dependent, and nitroprusside, which is endothelium-independent. Experiments were carried out in 12 healthy volunteers. Graded doses of rHuEPO (25, 50, 500 U/min), acetylcholine (7.5 and 15 micrograms/min), sodium nitroprusside (3 and 10 micrograms/min), and saline solution (sodium chloride 0.9%) were infused in the dorsal pedal artery of the lower limb. rHuEPO reduced the cutaneous temperature in a dose-dependent manner compared to the saline solution, thus suggesting that the hormone causes vasoconstriction. In contrast graded doses of acetylcholine and nitroprusside provoked vasodilatation: in fact both increased the cutaneous temperature compared to controls in a dose-dependent manner. The infusion of vasoconstrictive doses of rHuEPO in association with acetylcholine (15 micrograms/min) reverted the increase in the cutaneous temperature induced by the endothelium-dependent vasodilator. In contrast rHuEPO administered in combination with nitroprusside failed to block the vasodilatation induced by the endothelium-independent vasodilator. Therefore our data suggest that rHuEPO exerts an indirect vasoconstrictive effect and that acetylcholine-induced vasodilatation, which is endothelium-dependent, is blunted by the vasoconstrictive activity of rHuEPO, thus demonstrating that the hormone may impair the synthesis of endothelial nitric oxide.

Acetylcholine↗
PubMedDate not supplied

Is apoptosis cause of pre-eclampsia?

Pre-eclampsia is the main cause of fetal and maternal morbidity and death associated with hypertension during complicating pregnancy. During physiological pregnancy, the immunological system undergoes secondary modifications, with an "exchange" between mother and fetus. Cytokines play an important role in the complex condition of partial fetal "rejection". It has suggested that the condition depend on immunological factors. In line with this hypothesis, apoptosis appear to play a key role in the pathophysiology of placental ischemia and the mechanism underlying this condition may be influenced by substances such as Bcl-2 which inhibits apoptosis. Neither aspirin nor calcium appear to improve maternal hypertension and proteinuria, although late ongoing trials may alter this view. At present, the condition can be resolved only by the end of pregnancy. Further studies are required in order to improve our understanding of these immunological mechanisms underlying hypertension during pregnancy, as the key to effective therapy may be their ability to "manipulate" them in an appropriate way.

Adult↗
PubMedDate not supplied

Environmental air pollution in an intensive care unit for nephrology and dialysis.

The quality of indoor air depends on external pollutant concentrations and on internal sources, such as heating and air conditioning systems, building materials, ventilation, cleaning products, personnel and their activity. This study assessed environmental air pollution in an intensive care unit (ICU) for nephrology and dialysis. Air-dispersed particulate pollution was measured using a gravimetric method and spectroscopic photocorrelation. Microbiological pollution was evaluated by passive and active collection. Particulate concentrations exceeded recommended limits in some of the environments. There was a prevalence of small particulates, which are the most harmful type of all. An overall evaluation of bacterial pollution showed low levels of contamination in some of the rooms. In none of the environments we were able to detect pathogens such as Aspergillus fumigatus, methycillin-resistant Staphylococci or toxin-producing fungi.

Air Microbiology↗
PubMedDate not supplied

Pentosidine, carotid atherosclerosis and alterations in left ventricular geometry in hemodialysis patients.

OBJECTIVE: To assess the relationship between advanced glycation end products (AGE) and cardiovascular damage in end-stage renal diseases. METHODS: Ninety-one hemodialysis patients who had been on dialysis treatment for at least six months were recruited for the study. Each patient underwent echocardiography and an echo-color Doppler study of the carotid arteries. We measured plasma pentosidine and related it to intima media thickness, atherosclerotic plaques and parameters of left ventricular geometry. RESULTS: Pentosidine was higher in patients treated by low-flux dialysis (31.0+/-16.6 pmol/mg protein) than in those treated by high-flux dialysis (25.4+/-7.6 pmol/mg protein), but this difference was of marginal statistical significance (P=0.08). On multivariate analysis, plasma IgG (beta=0.24, P=0.02) was the only independent correlate of plasma pentosidine. Intima media thickness and the number of atherosclerotic plaques were unrelated to plasma pentosidine. Mean wall thickness (beta=0.18, P<0.05), relative wall thickness (beta=0.20, P<0.05) and left ventricular end-diastolic volume (beta= -0.23, P<0.01) were independently related to plasma pentosidine. CONCLUSIONS: Pentosidine, a reliable marker of "carbonyl stress", is unrelated to intima media thickness and to the number of atherosclerotic plaques, but it is related to alterations in heart geometry. These data suggest that the effect of carbonyl stress on the cardiovascular system is complex and that the effects of AGE on the heart may be dissociated from those on the arterial system.

Arginine↗
PubMedDate not supplied

[Diverticular disease of the colon in peritoneal dialysis].

Colon diverticular disease is a very common pathology in western countries and represents a risk factor for septic-type complications, especially in peritoneal dialysis patients. We examined both diagnostic procedure and therapeutics options, either pharmacological or surgical. Ultrasonography, which is useful for the diagnosis of diverticulosis and diverticular disease, has been supported in the last few years by new imaging techniques, such as NMR and CT, that also find applications in the treatment of diverticulitis complications like peritoneal abscesses. Our emphasis is on the therapeutic perspective, either dietetic - based on the use of a fibre-rich diet and the infusion of liquids by intravenous injection - or surgical, such as the Hartmann procedure, single anastomosis with stomia conservation and laparoscopic and endoscopic treatment. These therapeutic approaches have reduced both morbidity and mortality rate and have emphasized how the reduction of surgical stress on the mesothelium promotes the recovery of the functional integrity and, consequently, faster resumption of peritoneal dialysis. In conclusion, diverticulosis alone is not a contraindication for peritoneal dialysis, but constitutes a risk factor for the continuation of this alternative treatment.

Anastomosis, Surgical↗
PubMedDate not supplied

[Growth factors and hematopoiesis. Physiopathology and clinical applications].

Recently biotechnologic progress has, through the technique of the recombinant DNA, allowed a low cost production of large amount of several growth factors. Such a large availability has made possible to either carry out deeper investigations on the physiopathology of the hemopoietic regulation and perform new therapeutic approaches under different pathologic conditions. The most interesting acquisition concerning the biology of hemopoiesis to which such investigations have addressed us is the inadequacy of the protocols adopted till now. Such protocols considered only a simple vision of an elective action of a given growth factor during an exact maturation period of a determined cell colony. On the contrary, it was possible to point out a close network of inter-relationship among the different factors, which sometime impedes a clear distinction for each single factor, between actions of competence and progression in the cell maturation phenomena. However, the present uncertainty pertaining to the regulation of hemopoiesis has not impede the performance of clinical trials with positive findings in several pathologic conditions. The administration of recombinant erythropoietin has for example allowed to intervene in a resolutive way on the anemia in uremic subjects, and seems giving satisfactory results also in subjects with non renal origin anemic conditions. Satisfactory results were also obtained through the use of the Granulocyte-Macrophage CSF and of the Granulocyte-CSF, which by preventing neutropenia have allowed the performance of more adequate chemotherapeutic protocols in neoplastic subjects. New interesting perspectives are now coming for the use of Interleukin-3 in the treatment of the aplastic anaemia.

Colony-Forming Units Assay↗
PubMedDate not supplied

[Respiratory function abnormalities in uremic patients].

Patients with end-stage renal disease treated by hemodialysis are exposed to continuous pulmonary insults of multifactorial origin. Alterations in respiratory drive, mechanics, muscle function and gas exchange are frequent in hemodialysis patients. Pulmonary dysfunction may be the direct consequence of circulating uraemic toxins or may result indirectly from volume overload, anaemia, immune suppression, extraosseous calcification, malnutrition, electrolyte disorders, and/or acid-base imbalances. We have emphasised how derangement of diffusing capacity represents the most frequent and important respiratory abnormality in haemodialysed patients. It has been postulated that some forms of selective damage in the alveolo-capillary wall interferes with alveolar gas exchange.

Humans↗